The Character Of Nuclear Localization Of Tomato JERFs Genes And Their Roles In Down-stream Genes Expression

Plant are exposed to a number of conditions that may adversely affect their growth and development. Both ethylene and salicylic acid, a plant defense signal, accumulate in plant during pathogen infection. Communication between these plant hormones modulate the expression of some pathogenesis-related(PR)protein. Gene Analysis of PR gene promoters has led to the identification of the 11-bp ethylene-responsive element which has been referred to as the GCC-box.We isolated a number of genes named JERFs which can encode transcription factors from tomato cDNA expression library using yeast-one-hybrid system .It has been demonstrated that this kind of DNA binding proteins can interact with GCC-box and regulate the expression of gene responsive to aboitic and biotic stresses.The transcription factors belong to AP2/EREBP family,they contain a highly conserved DNA binding domain consisting of 58 or 59 amino acid residues. In vivo, the JERFs also displayed an ability to active transcription . Using full-long DNA of JERFs as probe, with the result of Northern Blot, we found the JERFs were induced by ethylene.To investigate the cellular distribution of JERFs , we performed an in vivo targeting experiment by using JERFs-fused green fluorescent protein as a fluorescent marker, through Agrobacterium-mediated transformation method localization of the fusion protein were determined by visualization with a fluorescence micoroscope .The result proved the JERFs were localized to nucleus .To understand the biological function of JERFs as transcription factor in plant .We constucted the vector earring a CaMV35 promoter and JERF2 cDNA, After confirmation by PCR , the constructs were introduced into tobacco by Agrobacterium infiltration.The results of Northern Blot indicate that some PR genes containing GCCbox such as Osmotin,Prb-lb, GLA, CHN50 were expressed in unstressed transgenictobacco plant, but not detected in unstressed wild tobaccos, suggesting that JERF3 could act as a transcript!onal activator to regulate expression of GCC box-containing genes.